Method for shaping a seamless aluminum wheel rim

ABSTRACT

A method for manufacturing a seamless wheel rim includes the steps: firstly, to deeply draw a pre-cut circular aluminum alloy plate into a cup-shaped embryo body, punch out the bottom surface thereof to form a hollow cylinder, then put it into an expanding-pressing female die with an expanding die cavity at both ends thereof respectively, and finally press and expand the both ends of the embryo body by two sets of expanding-pressing male dies to form a seamless aluminum wheel rim in sequence.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method for manufacturing avehicle wheel rim, which is simpler and lower cost than a conventionalmanufacturing method.

[0003] 2. The Related Art

[0004] In the considerations of reducing the weight of a vehicle bodyand promoting its control and appearance, a vehicle wheel rim is mostlymanufactured by aluminum alloy material now. Although a conventionalmethod can manufacture a superior performance and appearance of aluminumwheel rim, it still exists some defects. For example the strengththereof cannot be further increased, the manufacturing processes thereofare too complicate, and the manufacturing cost thereof cannot bereduced. Three conventional methods for manufacturing an aluminum wheelrim and the defects thereof in reference to the accompanying drawingsare described as the followings.

[0005]FIG. 1 shows a first conventional gravity casting method formanufacturing an aluminum wheel rim. A wheel-rim-shaped mold cavity A1is pre-designed in a foundry mold A. Then a melting aluminum alloy ispoured into the mold cavity A1. After cooled, the casting is taken outfrom the mold A and is processed through a heat treatment and machiningprocedures to form a wheel rim. However using a foundry mold tomanufacture a wheel rim, it easily produces sand holes due to themelting aluminum alloy containing airs. When it is mounted to a wheeltire, a leak will occur. In addition, due to micron sand holes, it ishard to manufacture a wheel rim with chromate treatment to meet marketrequirements. That further results in a drawback of high manufacturingcost of wheel rim with chromate treatment.

[0006]FIG. 2 shows a second conventional welding and spinning method formanufacturing an aluminum wheel rim. Firstly, a rectangular aluminumalloy plate B is rolled up by a rolling machine to form a cylindricalshell B1, then joint the two ends thereof together by a welding process,and finally shape it into a wheel rim B2 by a spinning machine. Howeverthis method needs rolling up, welding and spinning procedures so thatthe manufacturing time and cost thereof are relatively higher.Furthermore, the strength thereof is weaker than that of a wheel rimmanufactured by the present invention.

[0007]FIG. 3 shows a third conventional spinning method formanufacturing an aluminum wheel rim, which first manufactures two wheelrim parts and then mounts them together using fixing devices. Firstly,two different sizes of aluminum alloy plates C are respectively spuninto a first wheel rim part C1 and a second wheel rim part C2. The firstwheel rim part C1 and the second wheel rim part C2 are then jointedtogether through a wheel disc, bolts and nuts. However the third methodneeds two times of spinning, drilling and jointing procedures. Thereforethe manufacturing time thereof cannot be further reduced. The conditionof a leak even a loose of the wheel rim may occur due to vibration inthe movement of vehicles. And the strength thereof is weaker than thatof a wheel rim manufactured by the present invention.

[0008] In view of the defects of the above conventional methods formanufacturing an aluminum wheel rim, the present invention provides witha more superior method to manufacture a higher strength, betterperformance and lower cost of wheel rim.

SUMMARY OF THE INVENTION

[0009] The present invention is to solve the defects that a wheel rimmanufactured by conventional methods has a higher manufacturing cost,the strength thereof cannot be further increased and the weight thereofis heavier.

[0010] A method for manufacturing a seamless wheel rim in accordancewith the present invention is to first deeply draw a pre-cut circularaluminum alloy plate into a cup-shaped embryo body, punch out the bottomsurface thereof to form a hollow cylinder, then put it into anexpanding-pressing female die with an expanding die cavity at both endsthereof respectively, and finally press and expand the both ends of theembryo body by two sets of expanding-pressing male dies to form aseamless aluminum wheel rim in sequence.

[0011] An object of a method for shaping a seamless aluminum wheel rimin accordance with the present invention is to provide with a one-moldconstruction wheel rim without seams on the surface thereof so that thestrength thereof can be increased and there is no leak problem.

[0012] A second object of the method for shaping a seamless aluminumwheel rim in accordance with the present invention is to use a fewermachine equipments and less manufacturing time to manufacture a moresuperior wheel rim and reduce the manufacturing cost thereof.

[0013] Another object of the method for shaping a seamless aluminumwheel rim in accordance with the present invention is to promote thestrength of an aluminum wheel rim to meet the requirement of a largesize of vehicle wheel with lightweight. For example, a 24″ casting wheelrim weighs 24 kilograms but a same size wheel rim manufactured by thepresent invention weighs only 18 kilograms.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a schematic diagram showing a manufacturing process of aconventional gravity casting method for manufacturing a wheel rim andthe structure thereof.

[0015]FIG. 2 is a schematic diagram showing a manufacturing process of aconventional welding and spinning method for manufacturing a wheel rimand the structure thereof.

[0016]FIG. 3 is a schematic diagram showing a manufacturing process of aconventional spinning method for manufacturing a wheel rim, which firstmanufactures two wheel rim parts and then joint them together by a wheeldisc in combination with bolts and nuts.

[0017]FIG. 4 is a schematic diagram showing a manufacturing process of amethod for manufacturing a wheel rim and the structure thereof inaccordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0018] Referring to FIG. 4, a method for shaping a seamless aluminumwheel rim in accordance with the present invention comprises thefollowing steps of:

[0019] (1) cutting an aluminum alloy plate into a circular plate 1;

[0020] (2) the circular aluminum alloy plate 1 being drew into acup-shaped embryo body 1A by a deep drawing die 2, wherein an end of theembryo body 1A is shaped into a cup-shaped cylinder 1A2 and the otherend thereof is an embryo expansion part 1A1;

[0021] (3) the bottom surface of the cup-shaped cylinder 1A2 beingpunched out to form a hollow cylinder; and

[0022] (4) the cup-shaped embryo body 1A being put into anexpanding-pressing female die 3 with an expanding die cavityrespectively at both ends thereof, and then pressed and expanded by twosets of expanding-pressing male dies respectively at both ends of theembryo body 1A to make the embryo expansion part 1A1 and the cylinder1A2 respectively form a first expansion part 1B1 and a second expansionpart 1B2 that construct a wheel rim 1B.

[0023] The detailed shaping steps are further described as thefollowings. As shown in FIGS. 1(a)-(d), an aluminum-plate (material No.6061) with a thickness 6-7 mm is selected as a work. It is pre-cut intoa circular plate 1. The circular plate 1 is shaped into a cup-shapedembryo body 1A by a deep drawing die 2, wherein an end of the embryobody 1A is shaped into a cup-shaped cylinder 1A2 and the other endthereof is an embryo expansion part 1A1. The diameter of the embryoexpansion part 1A1 is greater than that of the cylinder 1A2. The bottomsurface of the embryo body 1A is then punched out by a punch press toform a hollow cylinder. The embryo expansion part 1A1 is not a finalexpansion part of a wheel rim but a pre-shape similar to a continuousdie.

[0024] The expanding-pressing female die 3 is a die being able to beopened in lateral direction. Both ends of the die cavity of theexpanding-pressing female die 3 are penetrated through each other andrespectively forms a first expanding die cavity 31 and a secondexpanding die cavity 32 (refer to FIG. 1(d)). The shaping processcomprises that the cylinder 1A2 of the embryo body 1A is inserted fromthe first expanding die cavity 31 into the second expanding die cavity32 (referring to FIG. 1(e)); a first expanding-pressing male die 4 isextruded by an oil pressure machine into the expanding-pressing femaledie 3 downwards to make the embryo expansion part 1A1 further be shapedinto a final first expansion part 1B1 (referring to FIG. 1(f)); next,the embryo body 1A is turned over 180 degrees to make the hollowcylinder 1A2 upwards; a second expanding-pressing male die 4A isextruded by an oil pressure machine into the expanding-pressing femaledie 3 downwards to make the hollow cylinder 1A2 be shaped into a secondexpansion part 1B2 (referring to FIG. 1(g)); and after opening theexpanding-pressing female die 3, a shaped wheel rim 1B (refer to FIG.1(h)) is taken out. In view that the wheel rim 1B can operate after itis mounted to a wheel seat of vehicle, therefore it should be mountedwith a wheel disc that is mounted to the wheel seat of vehicle. Thewheel disc is not an appealed key point of the present invention.Therefore it is not described here.

[0025] The manufacturing method of the present invention only uses a setof drawing die and two sets of expanding-pressing dies to shape aseamless aluminum alloy wheel rim. The equipment and manufacturing coststhereof are very low. The wheel rim has a superior performance and veryhigh strength due to seamless.

[0026] The above statement is only for illustrating the preferredembodiment of the present invention, and not for giving any limitationto the scope of the present invention. It will be apparent to thoseskilled in this art that all equivalent modifications and changes shallfall within the scope of the appended claims and are intended to formpart of this invention.

What is claimed is:
 1. A method for shaping a seamless aluminum wheelrim comprising the following steps of: (1) cutting an aluminum alloyplate into a circular plate; (2) the circular aluminum alloy plate beingdrew into a cup-shaped embryo body by a deep drawing die, wherein an endof the embryo body is shaped into a cup-shaped cylinder and the otherend thereof is an embryo expansion part; (3) the bottom surface of thecup-shaped cylinder being punched out to form a hollow cylinder; and (4)the cup-shaped embryo body being put into an expanding-pressing femaledie with an expanding die cavity respectively at both ends thereof, andthen pressed and expanded by two sets of expanding-pressing male diesrespectively at both ends of the embryo body to make the embryoexpansion part and the hollow cylinder respectively form a firstexpansion part and a second expansion part that construct a wheel rim.2. The method for shaping a seamless aluminum wheel rim as claimed inclaim 1, wherein the thickness of the aluminum alloy plate is 6-7 mm.